I was a Christian until my mid-twenties. It took a little time to shake off the childhood conditioning. For the past fifty-odd years I've been an atheist.
Believing that "there must be a god" to have created the Universe places us in exactly the same place as the ancients who lacked the knowledge and modern education needed to understand why things are as they are. They attributed them to gods, sprites, fairies, and all manner of ghostly ghoulies. There are still things we don't know, of course, but we're getting closer all the time.
But being an atheist doesn't mean we can't also explore the spiritual side of our nature. I could list a whole string of personal experiences that defy explanation (sorry gang, "coincidence" and "self-delusion" go only so far) and which indicate that there may be something beyond the physical. It's one of the intriguing questions.
Those who prefer to believe in a guy-in-the-sky-who-grants-wishes certainly have plenty of candidates to choose from. For instance, in Iceland they've just built a temple to the old Norse gods. And why not? They're as valid as any other.